Mechanical classifier



R. J. HALL 2,172,792

MECHANICAL CLASSIFIER 3 Sheets-Sheet 1 Sqn. 12, 1939.

Filed Jan. 25, 19:53

attorneys Umm;

Sept. 12, 1939. R. JfHALL MECHANICAL GLAssIFIxsm 3 Sheets-Sheet 2 Filed Jan. 25, 1938 Sept. 12,4 1939.4

R. J. HALL MECHANICAL CLASS IFI ER s Sheets-sheet s Filed Jan. 25, 1958 Patented Sept. 12, *1939.V l

`PATENT OFFICE MECHANICAL carissnuaar mapa J. Hau. ma, s. Dak.

Application January z5, 193s, sername. isasss z claims. (ci. zoe-15s) 'I'he present invention relatesto improvements in a mechanical classifier and more4 particularly to the type useful for separating solid or sand particles from slimes or slurries containing the same.

An object of the invention is to provide a device for the mechanical separation of sand or coarse particles from sand-slime pulp in va more economical and eiiicient way than'has been heretofore known.

Another object is to provide a device of small f size relative to its capacity and which requires `a minimum of power and wash water to operate. Another object is to provide a device in which the only moving parts are slowlydriven Scrapers A further object is to employ an air and/or water lift to causethe movementof liquidin the classifier.

A still further object is to provide a method4 for Aclassifying particles containedin sand-slime pulp which comprises confining the slimes to the upper or settling chamber and admitting only the sludge settled out of the slimes to the lower or wash chamber. y i

In general, the device has two chambers, one of which is settling chamber and the other a washing chamber. n The settling chamber is disposed above the Washing chamber and cmmunicates therewith through a restricted openand is met by a counter-current ofwash water which cleans the particles to be' recovered. The heavier particles continue against the `wash counter-current and fall directly tothe bottom of the wash chamber from whence they are withdrawn. The washings include the lighter particles. The counter-current of Wash water drives the washings into a wellin the wash chamber and air admitted into the well serves to drive the washings up through a duct into the settling chamber. The washingsare allowed to settle along with the incoming slimes and further of the particles are recovered therefrom. The washings also act to dilute the slimes and make it easier to separate the heavy particles in the settling chamber. Q

The waste liquid is collected from the set- -the settling chamber of the classifier.

tling chambers by means of a launder which receives the upper .or .lighter portion of the liquid after it has settled in the settling chamber. With theforegoing and other objects in view, the invention will be morefully described here- 5 inafter, and will be more particularly pointed out in the claims appended hereto.- In the drawings, whereinv like symbols refer to like or corresponding parts throughout the several views,

Figure 1 is a centralvertical section taken on the line I--I of Figure 2.

Figure 2"is a horizontal section taken o n the line 2-2 of Figure 1. l

Figure 3 is a horizontal -section taken on the 15 line 3 3 of. Figure 1. Y

Figure 4 is an enlarged detail view in section taken on the line 4-4 of Figure 3.

Figure v5.v is la fragmentary central vertical section taken on the line `55 of Figure 2, and 20 Figure 6 is an enlarged detail view partly in section taken through the gland of the-scraper drive shaft.

Referring now to the drawings and particularly l to Figure 1, I0 designates a tray which forms 25 The tray is shown in the form of a truncated cone but it may also be flat. At the periphery of the'. tray III is placed'a launder II over the lip I2 of whichl liquid can ow. At one or more. points 30v I4 which forms the washing chamber of `the 35 .A

classifier.

'I'he settling vchamber formed-by the tray` I0 is to provide a greatv bottom area and thetray is therefore quiteshallow in proportion to its diameter. The wash' chamber formed by the 40 cylindrical vessel I4 is, on the other hand, designedto secure a substantial vertical dimen- A sion. The vessel Il is also shown provided with a conical bottom to assist in collecting the particles which settle thereon. fThe central part of 45 the bottom ef the vessel I4 is open and is provided with an outlet nozzle I5 which has a. gate valve I6 thereon.' y

A vertical shaft II is suspended through the central opening of the settling tray I0 upon an 50 upper bearing I8 and a' lower bearing I9 which are' suitably supported as by attachment to the building or the like. The shaft rII has, between the bearings I8 and I9, a flanged pulley 20 which is driven from a power source having a pulley of the settling tray I0, the shaft I1 has a spider 23 keyed thereto, as best shown in Figure 2. The

24 so that, when the shaft I1 is rotated clock-V wise as seen in Figure 2, sludge on the bottom of the tray I will be moved toward the center of the settling chamber. Of course, it will be seen that other.forms` of scraper blades may be used in place of the angularly disposed plows shown. At the lower end of the shaft I1, as shown in Figures 1 and 3, is keyed a second spider 26 which likewise has four radial sockets receiving arms 21 which carry angularly disposed plows or Scrapers 25. The spider 26, armsy '21, and scrapers 25' are smaller than those in the set,- tling tray and they are adapted to scrape settled particles from the bottom of the washingchamber into the nozzle I wheny the shaft I1 is rotated. Y

A feed well is formed at the center of the settling tray by a box 28, of generally cylindrical form, which is supported by a bracket 29 secured lto the support 30 whichh'olds the lower bearing for the shaft I1. The top of the box 23 is providedv with a central opening through which passes the shaft I1, and a side opening 3| which receives the discharge end of a feed pipe 32. As shown by the dotted liquid level lines in Figure 1, the sides of the box 28 extend down below the surface of liquid in the settling chamber.

There is, therefore, a constant supply of incoming liquid for the settling chamber so that the flow is even and uniform and the settling material will not be disturbed by the admission of fluid.

Above the spider'23, on the shaft I1, is keyed a feed apron 33 the peripheral portion of which extends downwardly and under the edges of the box 28. A number of guides 34 are located on the edges of the feed apron and extend up and against the inner side of the box 28. The feed apron 33 causes the incoming liquid to iiow radially outwardly into the settling chamber and prevents 'direct ow of this incoming liquid down through the central opening of the tray I0. Below the spider 23, as seen in Figure 5, is an air reservoir 35 which is an inverted cylindrical vessel having an outwardly flaring skirt portion at the bottom. As shown in Figure 6, the upper wall of the reservoir 35 is held to the shaft I1 through a clamp having an upper male member 35 and a lower female member 31. The female member ,contains packing which -is adapted to be tightened against the shaft I1 when the bolts 33 are taken up. This maintains an air-tight joint below the surface'of the liquid in the settling chamber. Between the feed apron 33 and the air reservoir 35 are placed a number of vertical pipes 39 which pass through the 'ange of the spider 23, as shown in 'Figure 2, and which extend above the level of liquid in the feed chamber and extend down a substantial distance into the air reservoir. 'I 'he pipes 39 may be threaded into nuts 40 secured to the feed apron so as to permit vertical adjustment of the pipes. Of course, the joints of the pipes 39 with the reservoir 35 are made air-tight to preventv leakage of air from the reservoir.

vpasses through the wall of the vessel I4.

- mitted through the nozzles 44.

2,172,792 2| through the medium of a belt 22. At the levell An air supply pipe 4I connected to a source of compressed air extends up into the air reservoir 35 above the bottom of the pipes 39.

Around the outside of the vertical washing chamber are placed two circular wash water feed lines 42 and- 43 respectively. These feed lines connect with nozzles 34 which extend through the sides of the vessel I4 and are directed'upwardly and centrally of the wash chamber. The nozzles are directed substantially at the air reservoir 35.- Each of ,the nozzles 34 is provided with a valve 45 which permits obtaining the desired pressure in the' counter-current of wash water produced; Figure 4 shows the connectionbetween' one of the feed pipes 43 and one of the nozzles 34. 'Ihe valve 45 is connected through a nipple 45 to the feed pipe 43. A short nipple 41 on the opposite side of the valve connects with a length of rubber or other flexible hose 33. A short nipple 49 in the opposite end of the rubber hose 43 connects to a nut 53 which The rubber hose 43 will be secured lto the nipples 41 and 49 respectively'bymeans of hose clamps 5I of well known type. 0n the interior of the vessel I4 the nozzle 44 is connected to thenut 50 by means of the coupler 52.

In operation, sand-slime pulp or slurries containing heavy particles worth recovering are admitted through the feed pipe 32 into the top of the feed box 25. The liquid flows down upon the apron 33 andradially outward to fill the settling tray I0. The wash chamber comprising the vessel I4 will be filled with clear wash water ad- The incoming feed liquid will not pass down into the wash chamber tc any substantial extent. Inl the relatively quiet settling tray I0 heavy particles together with entrained slime and waste fall to the bottom of the tray I0 as a thick sludge. The lighter fluid rises to the top of the tray I0 and overows the lip I2 into the launder II from which it is removed through the pipe I3. The shaft I1 is being revolved and the scrapers 25 move the deposited sludge along the bottom of the tray I0 toward the narrow annular gap 53 which exists between the side of the air reservoir 35 and the bottom of the tray I0. The sludge falls by gravity down through the opening 53 and is directed toward the nozzles 44 by the outilaring skirt of. the air reservoir. This sludge consists of heavy particles and also of lighter particles both types of which are surrounded and contaminated by the slime. As the sludge drops towards the nozzles 34 wash water emerging from the nozzles produces a strong washing counter-current which tears the slime from the particles. The heavy'particles fall by gravity through the counter-current while the `lighter washed particles are drivencentrally and upwardly of the vessel.

In the meantime, air has been admitted through the pipe 4I into the air reservoir 35 from which it displaces apart of the liquid. As further quantities of air are introduced the liquid level is driven down until the air can escape'upward through the pipes 39 into the feed box 25.

Due to the violent nature of the escape of air washings which consist of slime together with the lighter particles pass upwardly through the pipes 39 into the feed box 28 in which they mix with the incoming feed solution `and pass into the settling tray I B. The slime being light rises to the top of the liquid inthe tray llland overflows the lip I2 into the launder. Light particles are thus kept out of the product and eventually find their way into the launder H and are re- -moved along with the other washings.

The Scrapers 25 collect the heavy particles at the bottom of the vessel H into the discharge nozzle I from which -they may be removed by the opening of the valve I6. The product consists only of heavy clean particles. The lighter particles, slime, wood chips and other contaminating substances are washed away into the launder Il.

The apparatus above described permits the obtaining of the objects previously stated and provides means for mechanically classifying or separating heavy particles from sand-slime pulp with the minimum amount of power and wash water. The only moving parts are the Scrapers at the bottoms of the two chambers and thesel are driven at a speed of from l to 3 revolutions per minute. Movement of liquid from the wash chamber to the settling tray is accomplished without friction by the use'of the air lift. Wash water and' washings are mixed with the incoming liquid to dilute it and dispose it for settling in the tray Il). All washings are removed through the single launder Il. The entering liquid lis substantially excluded from the wash chamber by the provision of a narrow angular opening 53 which constitutes the only communication for liquids between the chambers, aside from the air lift. The sluge vfalling through the opening 53 passes directly into the current from the nozzles 44 and is driven thereby, or tends to be driven up into the air reservoir. The coarser particles are of'suilicient weight to overcome the washing current and fall through it to the bottom of the vessel il. r

Lighter particles, slime and undesirable impurities of low density are driven upV into the air reservoir and cast up into the feed box 28 ending up eventually in the launder. vice is `designed for continuous operation at high eiliciency and 1 ow cost. It is of small size and delivers a uniform product. No intermediate size product is produced since the only particles that can be recovered are those of sufficient weight to fall through the washing counter-current thrown by the nozzles 34. Of course, for

The de-' classifying diierent weight particles the force of the washing current fiowing from the nozzles M may be Varied by the adjustment of the valves '45.

It is obvious that various changes and modifications may be made in the details of construction and design of the above specifically described embodiment of this invention without departing from'the spirit thereof, such changes and modifications -being restricted only by the scope of the following claims.

What is claimed is:

1. A classifier comprising a settling chamber with atray of relatively large bottom area, a Washing chamber of substantial depth disposed beneath said settling chamber, means for inftroducing liquid containing materials to be classified into said settling chamber, said tray communicating with the upper part of said washing chamber through an annular restricted opening in the bottom thereof, means for collecting heavy settled material in said tray and moving the same into said annular opening, whereby the heavy material falls into said washing chamber, a plurality of spaced wash nozzles disposed vcircumferentially about said washing chamber and directed upwardly to produce a wash counter-current of liquid adapted to strike the heavy material entering the washing chamber from the settling chamber, and means in the upper part of said washing chamber for collecting the washings and elevating the same to said settling chamber. A i.- l

2. A classifier comprising a settling chamber, a'washing chamber disposed beneath said settling chamber, said chambers communicating through an opening in the bottom of said Settling chamber, means for introducing liquid containing materials to be classified into said settling chamber, means for collecting heavy settled materials in the settling chamber and moving the material to said opening in the bottom of said settling chamber, means for restricting the opening in said settling chamber to cause the heavy settled materials to fall into the washing chamber in a relatively narrow stream, washl ing means including nozzles directed upwardly to throw a washing current of liquidagainst the heavy materials falling through said Washing chamber, and means for receiving the washing -current in the upper part of said washing chamber and for elevating the liquid and washings carried by said current to the said settling charnber.

RALPH J. HALL. 

